The invention relates to presses and more particularly to presses for pressing connectors into circuit boards.
Presses have been used to press connectors into circuit boards for so-called xe2x80x9cpress-fitxe2x80x9d type connections. For such connections, a connector includes contact pins and a circuit board includes corresponding holes to receive the contact pins. The press provides the force and motion to press the contact pins into the holes of the circuit board. The connector may be pressed to a specified position or to a specified force.
One problem with pressing the connector to a specified position is that it takes some amount of setup time to determine the specified position. For example, a user typically measures the circuit board thickness with a micrometer, measures the height of the connector, determines the current position of the press, and calculates and enters a position into a controller. Such a process may take an unacceptably long time. Further, such a process may result in an unacceptable amount of incorrectly pressed connectors due to measurement error, calculation error, data entry error, or the like. Therefore, a need exists for a user-friendly way for a press to determine a specified pressed position.
Pressing the connector to a specified force presents another problem. To adjust the pressing depth, a user either enters a force threshold or a force-distance ratio threshold. Such concepts may be difficult to comprehend and therefore may lead to errors and incorrectly pressed connectors. Therefore, a need exists for a user-friendly way to adjust a force based threshold.
Yet another problem exists with pressing multiple connectors to a force based threshold. Conventional presses are typically configured to press one connector at a time. To simultaneously press multiple connectors into a circuit board, a user typically looks up the force threshold for one connector type and multiplies by the number of connectors to determine a total force. The process becomes more complex when more than one type of connector is to be pressed. Moreover, if the connectors are of different heights, the press may be used in a multi-stage technique, pressing the smallest connectors on the first stage, then pressing the next larger connectors on the next stage, etc. Such multi-stage pressing may take an unacceptable amount of time. Therefore, a need exists for a user-friendly technique for simultaneously pressing multiple connectors into a circuit board.
Another problem that exists with pressing multiple connectors is that many presses cannot provide full capacity pressing force if the connectors are not located symmetrically about the center of a pressing platen. That is, if a connector is located at an end of the pressing platen, the press may not be able to press at its full capacity. Therefore, a need exists for a press that can provide near full capacity pressing force, even with an asymmetrical load.
The invention is directed to user-friendly systems and methods for learning a specified pressed position, adjusting a force based threshold, simultaneously pressing multiple connectors into a circuit board, simultaneously pressing multiple connectors of various heights into the circuit board, and to a press that can provide near capacity pressing force, even with an asymmetrical load.
According to an aspect of the invention, a press is provided for pressing a connector into a circuit board. The press comprises a linear motion source, a platen mechanically coupled to the linear motion source, and linear guides mechanically coupled to opposite sides of the platen to provide for asymmetric forces about the center of the platen. The linear motion source may comprise a servo motor and a ball screw that converts the motor rotation to linear motion. Each linear guide may comprise a linear bearing.
According to another aspect of the invention, a method is provided for adjusting a connector pressed depth in a press. The method comprises displaying a slider bar on a user interface. The slider bar represents a pressing force based threshold. An adjusted pressing force based threshold is received from the user interface via the slider bar. A press force is determined (e.g., measured) and platen motion is stopped if the determined press force is greater than the adjusted pressing force based threshold. The slider bar may comprise a first arrow that increases the pressing force based threshold and a second arrow that decreases the pressing force based threshold. The adjusted pressing force based threshold may be limited between a first limit value and a second limit value.
According to another aspect of the invention, a method is provided for adjusting a connector pressed depth in a press that presses a connector into a circuit board. The method comprises receiving an indication that a pressing platen has been positioned at a position wherein the connector is pressed in the circuit board. A value corresponding to the connector pressed position is determined and stored. The value may be a position value or a force value. The position value may be determined by reading an encoder value and converting the encoder value to a linear position value. The force value may be determined by measuring a value from a load cell, converting the measured value to a force value, and determining a maximum force value based on the converted force value.
According to yet another aspect of the invention, a method is provided for simultaneously pressing a plurality of connectors into a circuit board. The method comprises determining a plurality of connector types to be pressed into the circuit board. A quantity of each connector type is determined. A pressing force based threshold for each connector type is determined. A total force based threshold is determined based upon the determined quantities and pressing force based thresholds. The platen may be caused to move in a direction to press the plurality of connectors into the circuit board. A force acting upon the platen is determined (e.g., measured) and platen motion is stopped if the determined force is equal to or greater than the determined total force based threshold.
According a further aspect of the invention, an apparatus is provided for simultaneously pressing a first connector having a first connector height and a second connector having a second connector height into a circuit board. The apparatus comprises a platen, a first fixture, and a second fixture. The first fixture is coupled to the platen and has a height such that first connector height and the first fixture height sum to a predefined height. The second fixture is coupled to the platen and has a height such that second connector height and the second fixture height sum to about the same predefined height, whereby the first and second connectors can be simultaneously pressed into the circuit board.
The above-listed features, as well as other features, of the invention will be more fully set forth hereinafter.